Thank you All,

The following address summarizes all the necessary information, I
believe. Can you please validate that it is correct?
http://www.dcast.vbox.co.uk/cpm.html

I like the usage of the eighth bit on the three extension letters!

My understanding is:
- standard GCR encoded disk
- 35 tracks / 16 sectors with a specific interleave
- a block is a set of 4 sectors
- a block is 1024 bytes long
- block number 0 starts on track 3, sector 0
- blocks 80 to 8F are reserved for cp/m (tracks 0 to 2)
- two blocks reserved for the directory (blocks 0 and 1)
- a deleted file entry holds $E5 at offset 0
- there are no load address nor file length
- file length can be determined by the number of blocks)

If I understand correctly, the rc byte (offset +F) holds the number of
128-byte records in a file. I would have thought it held the number of
1024-byte blocks. Am I wrong?

As the AppleDisk5.25 driver works with 256 and 512-byte blocks, that
requires some changes... More ProDOS than DOS 3.3 or RDOS.

Can someone create a cp/m disk which contains only one big file (the
biggest that can be created) ? I would like to validate the value of a
file entry at offset +C. That value is 1 when the file is bigger than
16 blocks but which value is this if the file is bigger than 32 or 48
blocks?

Thank you in advance.

antoine

nb. email address can be found on brutal-deluxe.fr
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